Adds pgvector support to the postgres storage adapter without affecting
local or standalone tiers:
- `StorageConfig` postgres variant gains optional `enableVector: boolean`
- `PostgresAdapter.migrate()` runs `CREATE EXTENSION IF NOT EXISTS vector`
via `db.execute(sql)` BEFORE migrations when `enableVector === true`
(so vector-typed columns are creatable in the same migration pass).
Idempotent — safe to re-run on already-installed extension.
- `vector` custom type in `@mosaicstack/db/schema` is now exported so
downstream packages can declare vector columns in their own schemas.
- `DEFAULT_FEDERATED_CONFIG.storage.enableVector = true` so the federated
default flows through the adapter.
- `detectFromEnv()` restructured: `MOSAIC_STORAGE_TIER` is now checked
BEFORE the `DATABASE_URL` guard so `MOSAIC_STORAGE_TIER=federated`
alone returns the federated default config instead of silently
misrouting to local. Same applies to `=standalone`. With
`DATABASE_URL` set, the URL is honored and `enableVector` is preserved
on federated.
- `detectFromEnv` is now exported for direct test access.
Tests:
- 4 PostgresAdapter unit tests cover: extension SQL issued when enabled,
not issued when disabled or unset, ordering (extension before
runMigrations). Assertion uses Drizzle's `toSQL()` with documented
fallback for older versions.
- 4 detectFromEnv tests cover the four env-var permutations.
- 1 federated default constant test.
No behavior change for local or standalone tier deployments.
Refs #460
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
